From mcvittie at snf.stanford.edu Fri Jun 11 11:55:00 2004
From: mcvittie at snf.stanford.edu (Jim McVittie)
Date: Fri, 11 Jun 2004 11:55:00 -0700
Subject: Voluteer needed to run AMTEtcher Arc Subpression Tests
Message-ID: <40CA0004.805D245D@snf.stanford.edu>
Amtetcher Users,
We are still having lots of so called arcing problems with the
Amtetcher. We have tried lots of things to correct the problem but so
far nothing has worked. I believe it is actually a hollow cathode effect
where we are getting a temporary plasma filament going from the plasma
to the hexode or cathode through small spaces between the plastic
shields covering the hexode. Exactly why these filament are forming so
often now compared to the past, I do not know. Mostly likely some
internal component is failing or has changed. Rather than taking the
whole system apart to find this component, I would like to try a few
more less disruptive tests.
My latest thought is that we may be able to suppress this effect if we
switch the rf power control from constant bias voltage (-530V) to
constant power. The thought here is that when a hollow cathode filament
forms, it probably lowers the bias voltage which causes the delivered
power to increase. In the constant power mode, the power would not
increase and hopefully this would help kill or subpress the filament.
I am looking for a volunteer, who could run some process tests for me to
see if idea will work without affecting the process results.
Thanks, Jim
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From mcvittie at snf.stanford.edu Thu Jun 17 08:55:27 2004
From: mcvittie at snf.stanford.edu (Jim McVittie)
Date: Thu, 17 Jun 2004 08:55:27 -0700
Subject: Intermediate solution for Arcing on AMT-Etcher
Message-ID: <40D1BEEF.CB96C5FA@snf.stanford.edu>
AMT-Etcher Users,
As you know, we have been experiencing a lot of so called arcing on the
AMT-Etcher. It is to the point that it is occurring daily. I did some
tests yesterday and was able to run process #3 three times without
arcing. I changed both the process and the loading procedure. Until we
have a better solution, I want all users to make these changes in their
use of the tool. The changes are as follows:
1. Lower the maximum bias voltage setting to **** ?500 volts ****. This
will have a small affect on oxide etch rates but it will be worth it if
it avoids arcing. There was an etch rate test done last night but I do
not have the results. I expect the etch rate reduction to be in the
range of 5%.
2. Push trays up during loading. Part of the arcing problem is due some
worn parts which have increased the horizontal gap between the plastic
pieces at the top of the trays after they are loaded. For now to reduce
this gap, where the arcing occurs, I want you to push or pull up on the
bottom of the trays as you chip or clamp the top of the trays. This
should minimize the gap and thus reduce arcing.
Thanks, Jim
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From latta at snf.stanford.edu Wed Jun 30 17:04:49 2004
From: latta at snf.stanford.edu (Nancy Latta)
Date: Wed, 30 Jun 2004 17:04:49 -0700
Subject: New stand-by recipe- PLEASE READ!
Message-ID: <40E35521.2040406@snf.stanford.edu>
Dear Fellow Amtetcher Users,
First, thank you for hanging in there with us as we have tried to
address the arcing problem with the tool. It has been frustrating for
everyone.
Elmer has performed various tests with the clean recipe and has come up
with a method of cleaning and seasoning the chamber after use. He has
not been able to make the machine arc since trying this modification to
the stand-by ('holding'- process2) recipe.
Here is his description of the new recipe:
Modified the standby recipe (recipe 2) to perform a clean and seasoning
prior to going on HOLD. The clean is a 3 step clean and a seasoning.
1st clean- 45 mT, 1400 W for 1 minute : this step fixes the pressure
limit fault experienced when running at 30 mT.
2nd clean- 30 mt, 1400 W for 4 minutes
3rd clean- 70 mT, 1400 W for 3 minutes
seasoning- recipe 3 for 2 minutes
What this means for you, besides not having the arcing problem, is that
at shutdown, the recipe will take longer to get to' holding'. If you
disable the tool before it achieves 'holding' it will stop the recipe.
It will take about 20 minutes to get Process 2 to the holding step where
it is safe to disable.
Please let us know if you have any questions about this very important
change.
Thanks,
-Nancy